Potassium iodate (KIO3) is an ionic inorganic compound with the formula . It is a white salt that is soluble in water.
It can be prepared by reacting a potassium-containing base such as potassium hydroxide with iodic acid, for example:[1]
It can also be prepared by adding iodine to a hot, concentrated solution of potassium hydroxide:
3 I2 + 6 KOH → KIO3 + 5 KI + 3 H2O
Or by fusing potassium iodide with potassium chlorate, bromate or perchlorate, the melt is extracted with water and potassium iodate is isolated from the solution by crystallization:[2]
KI + KClO3 → KIO3 + KCl
The analogous reaction with potassium hypochlorite is also possible:[3]
KI + 3KOCl → 3KCl + KIO3Conditions/substances to avoid include: heat, shock, friction,[4] combustible materials, reducing materials, aluminium, organic compounds, carbon, hydrogen peroxide and sulfides.
Potassium iodate is sometimes used for iodination of table salt to prevent iodine deficiency. In the US, iodized salt contains antioxidants, because atmospheric oxygen can oxidize wet iodide to iodine; other countries simply use potassium iodate instead.[5] Salt mixed with ferrous fumarate and potassium iodate, "double fortified salt", are used to address both iron and iodine deficiencies.[6] Potassium iodate is also used to provide iodine in some baby formula.[7]
Like potassium bromate, potassium iodate is occasionally used as a maturing agent in baking.[8]
Potassium iodate may be used to protect against accumulation of radioactive iodine in the thyroid by saturating the body with a stable source of iodine prior to exposure. Approved by the World Health Organization for radiation protection, potassium iodate (KIO3) is an alternative to potassium iodide (KI), which has poor shelf life in hot and humid climates. The UK, Singapore, United Arab Emirates, and the U.S. states Idaho and Utah all maintain potassium iodate tablets towards this end. Following the September 11 attacks, the government of Ireland issued potassium iodate tablets to all households for a similar purpose.[9]
| Over 12 years old | 130 | 170 | |
| 3 – 12 years old | 65 | 85 | |
| 1 – 36 months old | 32 | 42 | |
| < 1 month old | 16 | 21 |
Potassium iodate is not approved by the U.S. Food and Drug Administration (FDA) for use as a thyroid blocker, and the FDA has taken action against US websites that promote this use.[10] [11]
Potassium iodate is an oxidizing agent and as such it can form explosive mixtures when combined with organic compounds.[1]